In scroll compressors it is necessary or at least highly desirable to provide an axial compliance mechanism which effects proper sealing of the wrap tips against the adjacent scroll base even though pressures of several hundred psi are typically developed in the pressure continuum, i.e., the compression pockets which are continuously formed, compressed, discharged and reformed between the scrolls. This mechanism, most often, comprises an axial compliance pressure chamber by which forces are exerted against the axially outer surface of the base of one of the scrolls which significantly counteract the forces which tend to axially separate the scrolls. One of the greatest difficulties encountered with the use of such a chamber is the problem of maintaining its seal during axial compliance movement of the scroll selected and mounted for such movement.
Also, in scroll compressors, the high pressure pockets of the pressure continuum are typically responsible for imparting strong forces, i.e., tangential, radial, or lateral against the wrap of the orbiting scroll which tend to tip the scroll on its longitudinal axis. This tipping action is often exacerbated in compressors wherein the orbiting scroll is the one set up for axial compliance motion since greater clearances of the drive shaft eccentric and the bearing means on the scroll, e.g., when employing radial compliance structures, can lead to increased looseness in the system and greater allowance for tipping of the scroll on its axis. This tipping usually results in loss of sealing between the wrap walls and between their tips and the juxtaposed base of the other scroll, and thus a loss of efficiency, as well as excessive wear contact of the orbiting scroll with the stationary scroll. Also, increased axial compliance force becomes necessary to compensate for the non-planar mating of the wrap tips and juxtaposed scroll base, and proper continued sealing of the axial compliance pressure chamber is thus compromised. The aforementioned novel structure of the present invention dramatically diminishes the tendency of the orbiting scroll to so tip while affording a greatly simplified and economical structure to certain aspects of the compressor, particularly the pressure chamber seal means, as will hereinafter become evident.